This invention relates to the use of alkaline proteases in commercial laundry methods and to compositions for use in commercial laundry methods which contain alkaline proteases.
The textile detergents used in commercial laundries differ in many ways from the detergents normally used domestically. Commercial laundries employ large washer systems which operate either cyclically in response to a timer or continuously and have a very high laundry throughput. These commercial washer systems use different detergent combinations depending on the type of textile and the degree of soiling with the detergent being dispensed in measured amounts into the washing solution in various washing stages such as wetting, prewashing, clear washing and rinsing. The need to utilize water and energy economically has made it necessary to develop for commercial laundering special partly formulated detergent combinations which can be adjusted optimally for the particular washing stage depending on the type and soiling of the textiles to be washed.
It has long been known to use protease-containing detergent compositions in commercial laundries, for example for cleaning hospital laundry contaminated with blood or protective clothing from meat-processing operations. Because the conditions in commercial laundry methods are more severe than in domestic washing machines, particularly high demands are made of the proteases used therein. In addition to good stability and activity at highly alkaline pH values, proteases to be used in commercial laundry systems should have a temperature stability which is sufficiently high to produce good washing results for the particular laundering cycle at low concentration for the maximum length of time at the high temperatures which prevail in commercial laundry methods. In addition, the alkaline proteases used should have minimum sensitivity to the detergent ingredients customary in commercial laundry methods, such as, for example, surfactants, bleaches or disinfectants. Thus, there has remained a need for alkaline proteases which are suitable for commercial laundry methods.